首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Why don’ t birds get lost on their long flights from one place to another? Scientists have puzzled over this question for a long
Why don’ t birds get lost on their long flights from one place to another? Scientists have puzzled over this question for a long
admin
2015-01-10
61
问题
Why don’ t birds get lost on their long flights from one place to another? Scientists have puzzled over this question for a long time. Now they’ re starting to fill in the blanks.
Not long ago, experiments showed that birds use the sun to guide them during daylight hours. How do birds fly at night? Tests with artificial stars have proved that certain night-flying birds are able to follow the stars in their long-distance flights.
A dove had spent its lifetime in a cage and had never flown under a natural sky. But it had an inborn ability to use the stars for guidance. The bird’s cage was placed under an artificial star-filled sky. The bird tried to fly in the same direction as that taken by his outdoor cousins. Any change in the position of the artificial stars caused a change in the direction of his flight.
But the stars are apparently their main means of navigation. When the stars are hidden by clouds, they apparently find their way by such landmarks as river courses, mountain ranges, coast lines. But when it’ s too dark to see these things, the doves circle helplessly, unable to find their way.
The reasons why birds don’t get lost on their long flights______.
选项
A、have been known to scientists for years
B、have only recently been discovered
C、are known by everyone
D、will probably remain a mystery
答案
B
解析
题干意为“在长途飞行过程中鸟儿不会迷路的原因______。”从文章第一段最后一句话“Now they’re starting to fill in the blanks.”可以得出答案B。A项“科学家们已经掌握多年了”;C项“每个人都知道”;D项“将有可能继续是一个谜”,都不符合文意。
转载请注明原文地址:https://kaotiyun.com/show/to0K777K
本试题收录于:
大学英语三级B级题库大学英语三级分类
0
大学英语三级B级
大学英语三级
相关试题推荐
I______toposttheletterthatIwrotetomyparents,butIwastoobusy.
Thisletteriswrittento______.Comparedtothepreviousproducts,thenewlydesignedones______.
ItgivesusmuchpleasuretosendyouthegoodsaskedforinyourletterofSeptember10.
A、It’ssixo’clock.B、Itisnotmyfault.C、Thetrafficwasterrible.D、Thebuswasontime.C“Jim,whyareyousolatetoday?”翻
Asan(experience)______teacher,heknowsexactlyhowtodealwiththepoorstudents.
A—actionadvertisingB—airportadvertisingC—billboardadvertisingD—businessadvertisingE—directmailadvertising
Theherowouldratherdiethan(give)______in.
______isthequestionnobodycananswer.
(judge)______fromhischeerfullook,Iamsurethattheyhavewonthegame.
Ifyouworkfrom9:00a.m.to4:30p.m.everyday.Whichschoolwillyouchoose?The21stCenturyEnglishTrainingCenterisdi
随机试题
引起女阴萎缩性营养不良的原因主要是:
细菌的致病性强弱主要取决于()。
交换的积分次序.
根据个人所得税法律制度的规定,下列各项中,暂减按10%税率征收个人所得税的是()。
图中最陡峭的地方是()。
真正淡泊的人是不为人所知的,为人所知的就不可能是淡泊。因为淡泊在本质上是力排外物喧扰的纯个人的境界追求,是致力于内心世界的内敛的深度反省,是相对物欲红尘悄无声息的静默和顿悟。人内心深层的心理思维是不为外界所感知的,也是不愿被揭示披露的高级隐私,谁淡泊谁不淡
电影类型是怎样形成的?类型电影有何特征?
即使对程序的所有路径都进行了测试,程序也可能存在没能检查出来的缺陷,其原因可能是______。A)程序可能会因为缺少某些路径而存在问题B)即使是穷举路径测试也绝不能保证程序符合其设计规格说明C)穷举路径测试也可能不会暴露数据敏感错误D)以上
Youmaysaythatthebusinessofmarkingbooksisgoingtoslowdownyourreading.(31)probablywill.That’soneofthe(32)fo
______referstoabranchoflinguisticsconcernedwiththeuseoflanguageinsocialcontextsandthewaysinwhichpeopleprodu
最新回复
(
0
)